In recent years, a significant industry has developed which involves the application of customer-selected designs, messages, illustrations, and the like (referred to collectively hereinafter as “images”) to substrates through the use of heat transfer papers. The images are transferred from the heat transfer paper to the substrate through the application of heat and pressure, after which the release or transfer paper is removed. Typically, a heat transfer material includes a cellulosic base sheet and an image-receptive coating on a surface of the base sheet. The image-receptive coating usually contains one or more thermoplastic polymeric binders, as well as, other additives to improve the transferability and printability of the coating.
The quality of the image formed on the image-receptive coating on the heat transfer material directly correlates to the quality of the image formed on the final substrate (e.g., an article of clothing). Digital electrographic toner printing (often referred to as laser printing) is a well-known method of printing high quality images onto a paper sheet. Another type of digital toner printing is called digital offset printing.
When utilizing a toner ink printing process, the printable surface (e.g., an image-receptive coating of a heat transfer sheet) is specially designed to fuse with the toner ink at the printing temperatures (e.g., typically from about 50° C. to about 120° C. but sometimes may reach as high as about 200° C.). This printable surface is designed to attract and adhere the toner ink from the printer. However, due to this affinity for the toner ink, the printable surface often picks up unwanted, stray toner ink from the printer. This stray toner ink can blur the image and provide unwanted background “noise” on the printable surface. When utilized with a heat transfer paper, any stray toner ink on the heat transfer paper will be transferred to the substrate.
As such, a need exists for a heat transfer paper which improves the quality of an image printed onto the image-receptive coating of a heat transfer paper.